Experimental and Numerical Study on the Effects of Frame Shapes and Stacking Sequence of Composite Plates Subjected to High- Velocity Impact

The behavior of different E-glass/epoxy plates has been experimentally and numerically (with the computer code LS-DYNA, three-dimensional (3D) transient deformations) studied the impact of steel spherical projectile (2.71gr, 8.7 mm diameter) at high velocity (280 m/s). Composite plates have sections with geometrical figures in the form of equilateral triangle, square, hexagon and circle. The result were obtained using gas gun machine and presented for two different cross-ply laminates ([0,0,90,90,90]s, type A, [0,0,0,0,90]s, type B) and transverse isotropic laminate ([0,36,72,-72,-36,0,36,72,-72,-36], type C) and semi transverse isotropic laminate ([0,72,-36,36,-72]s, type D). During the experiments we saw the highest energy absorption related to the square shape of type A, which is 99.8 percent has to absorb energy. Lowest energy absorption relate to the triangle type D, which is 58.4percent has to absorb energy. Ultimately based on the geometry of the environmental geometry and fiber length in each diagram in the amount of strain and strain rate considered as effective. On the other hand, the presence of several layers with identical orientation (type A, B) the effects of geometry on the strain rate decreases, and the degradation rate is reduced, in contrast with the presence of layers of different orientation (type C, D), the effects of geometry on the strain rate increases, and the rate of delamination increases. Most area destroyed input and output are related to the layer D and it is the reason for difference 72° and they create a large-scale delamination, which is geometric shapes-square and a circle with the effects of marginal in their and the surrounding environment contribute to this more. Diversity in the area of failure input, output and middle, and the quantity of output velocity of projectile, shows interaction geometry and structure is on the lay-up.

Keywords:

LS-DYNA (FEA) , Impact behavior , Ballistic test , Lay-ups of composite plate , Frame shapes